E2FREEFRAG(8)              System Manager's Manual             E2FREEFRAG(8)

NAME         top

       e2freefrag - report free space fragmentation information

SYNOPSIS         top

       e2freefrag [ -c chunk_kb ] [ -h ] filesys

DESCRIPTION         top

       e2freefrag is used to report free space fragmentation on ext2/3/4
       file systems.  filesys is the filesystem device name (e.g.
       /dev/hdc1, /dev/md0).  The e2freefrag program will scan the block
       bitmap information to check how many free blocks are present as
       contiguous and aligned free space. The percentage of contiguous free
       blocks of size and of alignment chunk_kb is reported.  It also
       displays the minimum/maximum/average free chunk size in the
       filesystem, along with a histogram of all free chunks.  This
       information can be used to gauge the level of free space
       fragmentation in the filesystem.

OPTIONS         top

       -c chunk_kb
              If a chunk size is specified, then e2freefrag will print how
              many free chunks of size chunk_kb are available in units of
              kilobytes (Kb).  The chunk size must be a power of two and be
              larger than filesystem block size.

       -h     Print the usage of the program.

EXAMPLE         top

       # e2freefrag /dev/vgroot/lvhome
       Device: /dev/vgroot/lvhome
       Blocksize: 4096 bytes
       Total blocks: 1504085
       Free blocks: 292995 (19.5%)

       Min. free extent: 4 KB
       Max. free extent: 24008 KB
       Avg. free extent: 252 KB

       Extent Size Range :   Free extents   Free Blocks  Percent
           4K...    8K- :           704           704     0.2%
           8K...   16K- :           810          1979     0.7%
          16K...   32K- :           843          4467     1.5%
          32K...   64K- :           579          6263     2.1%
          64K...  128K- :           493         11067     3.8%
         128K...  256K- :           394         18097     6.2%
         256K...  512K- :           281         25477     8.7%
         512K... 1024K- :           253         44914    15.3%
           1M...    2M- :           143         51897    17.7%
           2M...    4M- :            73         50683    17.3%
           4M...    8M- :            37         52417    17.9%
           8M...   16M- :             7         19028     6.5%
          16M...   32M- :             1          6002     2.0%

AUTHOR         top

       This version of e2freefrag was written by Rupesh Thakare, and
       modified by Andreas Dilger <>, and Kalpak Shah.

SEE ALSO         top

       debugfs(8), dumpe2fs(8), e2fsck(8)

COLOPHON         top

       This page is part of the e2fsprogs (utilities for ext2/3/4
       filesystems) project.  Information about the project can be found at
       ⟨⟩.  It is not known how to report
       bugs for this man page; if you know, please send a mail to  This page was obtained from the project's
       upstream Git repository 
       ⟨git://⟩ on 2017-09-15.
       If you discover any rendering problems in this HTML version of the
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       send a mail to

E2fsprogs version 1.43.6         August 2017                   E2FREEFRAG(8)